You are wrong. IPRs are much quicker and less expensive that district court litigation, which is what it replaces. If you're afraid of Big. Co.'s deep pockets, they're much scarier in district court! The PTAB is designed to be more efficient, quicker, and cheaper than district court, and it is by a long shot. And no, they can't file serial IPRs for the most part, there is strong estoppel that comes with an IPR proceeding to prevent just that very thing from happening. So if your patent is valid, then in less than a year and about $200k you can have that sucker gold plated and anointed by the PTAB and then enforce it to your hearts delight! Much better than several million $ and at least 2-3 years for a district court if you ask me. And if your patent is garbage, well you'll find that out quicker too and free up resources to go do something else.